Action of the Pulses of Shock Waves on the Structure and Superconducting Parameters of MgB2 Tapes

Resumo

The possibility of increasing the critical current of MgB₂ tapes containing carbon and oxygen additives under the action of shock waves produced by pulsed plasma in a Plasma Focus setup is demonstrated. The microstructure of the tapes and the chemical composition of superconducting layers in the initial state and after impact at different distances between the samples and the anode of Plasma Focus installation (from 20 to 45 mm) and the number of shocks (from three to five) are investigated. The regularities of the change in the critical current as a function of the magnitude of transverse and longitudinal magnetic fields in the range of 2–9 T are studied at 4.2 K. It is established that as a result of the impact and thermal action of the plasma, the superconducting interlayers become denser, the grains are fragmented, the composition is homogenized, and the chemical composition is changed. This promotes an increase in the critical current by 50–80 A in transverse magnetic fields of 2–3 T.